Recent commercial innovations in the liquid laundry detergent market include “unit dose” products, where detergent components are placed within a water-soluble polymer pouch. These unit dose products are characterized by high actives concentration, and low water content (typically less than 15%). In order to create such high active formulations, surfactants molecules are required that can exist in such compact spaces without causing adverse effects to formulation stability. Some of these adverse effects include increase in viscosity of the formulation, and interactions of the formulation with the encasing polymer (in most cases polyvinyl alcohol (PVOH)), resulting in undesirable gel blobs or undispersed flocs.
Current formulations generally contain one or more surfactants, typically anionic and/or nonionic surfactants or combinations thereof. A commonly used class of anionic surfactants are the linear alkylbenzene sulfonic acids (“HLAS”).
The acid group of HLASs is neutralized with various bases to obtain functioning surfactants (at about pH 7 or so). Some common examples of bases that are used in commercial surfactant applications are NaOH (giving LABS linear alkylbenzene sulfonate sodium salt). Known neutralized HLASs, such as LABS, however, are lacking in a number of areas. For instance, such compounds may exhibit the disadvantages indicated above, including undesirably high viscosity when formulated in a detergent composition, and/or formation of gel blobs or undispersed flocs resulting from interaction with the PVOH film.
The problem addressed by this invention is the provision of new alkylbenzene sulfonic acid salts that address various shortcomings of existing materials.